Been doing a bit of investigation and wondered if anyone could help. It would seem that the US Cooper S, US JCW and UK JCW share the same turbo while the UK Cooper S has something different, see part numbers below

RealOEM - Engine - country - Model - Prod Month - Turbo part number - Injectors part number
F56 B46 US Cooper S 09/2015 11658626637 13537639990
F56 B48 Britain Cooper S 09/2015 11658626636 13537639990
F56 B46 US JCW 09/2015 11658626637 13537639990
F56 B48 Britain JCW 09/2015 11658626637 13537639990


Any idea what's the next step to find out what the difference are between the two part numbers and if its worth upgrading a UK Cooper S to a JCW turbo?

 

I had read that the S and JCW turbos were the same, but wasn't aware of the UK thing. Could be a typo. Don't know of a way to check the specs.

 

Same on US side. Might have different parts number due to regulations or the ECU they are using , best way is to order up in the uk side and put them side by side. Measure the turbo and inlets. Dealership should help you over there. Also look at the name plate and cross ref the numbers.

 

Sorry for resurrecting this thread from dead but do we now the specific specs on both turbo's? I thought I read somewhere that the compressor wheel on the JCW turbo is like 2-3mm larger? This is the only thread that came up when I searched here that has this in the name of the thread.

 

 

Hmmm, so all they did for F56 JCW is install stronger and lower compression pistons and cranked up the boost a little? I was expecting bigger differences, how about the rods?

 

MINI does not tune like you expect, the lower compression 1:10 versus 1:11 is one part, the other part is a complete unique cooling system which guarantees the that the boost works !

 

Is the JCW's intercooler that much bigger/flows better that it's going to be a huge factor in the performance differences? And you are talking about that little side/fog lamp cooler that JCW's have? They still use the same turbo for JCW as in Cooper S, right? So that means that they have to up the boost somewhat to get that extra hp, right? Lower compression will prevent some pre-detonation so more power could be pushed out of it, right? I was wandering about those aftermarket pistons that just came for the F56 platform (https://www.lohen.co.uk/supertech-mi...r-cooper-s-jcw) - is it better for me as a F56 Cooper S owner to get aftermarket JCW pistons with the lower compression of 1:10.2 instead of 1:11 and have aftermarket tune that pumps up more boost or stay with standard Cooper S aftermarket pistons and don't push it too much. Assuming I install an aftermarket intercooler that would cool the intake air somewhat better than the stock on consecutive pulls (oil cooler can't be fitted unless the whole front bumper is swapped and I don't want to do that, and even then not sure if it's doable). If the pistons are the only thing other than extra cooling that separates Cooper S and JCW than getting JCW aftermarket pistons with lower compression could be a way to get a bit more performance out of the F56 Cooper S then. Are they both using the same rods?

 

The connecting rods are the same, you can buy OE JCW pistons

11 25 8 638 450

€192.92
a set of forged pistons from Mahle is around 1000 Euro, the BMW piston kit includes the pins, also you should consider than 9.5 if you customise them anyhow.
As the intercooler from JCW is bigger the actual radiator is smaller and get compensated with remote, so the Cooper S radiator is bigger (Height) and a aftermarket intercooler useful.

 

^Thanks for clarification. Yea, a friend of mine has his JCW at the dealership with a misfire issue that they are trying to fix for two weeks now and there might be an issue with the engine that would require the engine rebuild. Now, he does have down pipe and full exhaust, cai, ic and a certain stage 2 tune (he returned the stock tune before bringing it in for service) so they might not cover the repair. So that got me thinking that even stronger JCW pistons might not be up to task of handling stage 2 tunes, that's why I was considering getting aftermarket, even stronger pistons. But that's all in the future, I'm not going to modify my car much until the warranty expires anyways, just collecting information for now.

 

Thats ok - MINI parts are expensive, the warranty should be always considered ;-)

I can only say that a f56 with 300hp scoots, and my turbo is the same as on the Cooper S and JCW

 

I'm going to take a wild guess and say it's a bytetronik tune....

 

…meaning?

 

And you'd be wrong...I'm not saying anything else because we don't have a proof the tune did it.